Digital cytology means the digital conversion of a microscopic image of a cytology smear along with the acquisition of the clinical data and the patient’s metadata. The introduction of whole slide imaging (WSI) has given a new dimension to the digitization of images. WSI helps to view the slides at any magnification without losing the image features. WSI image is known as a digital slide which can be stored in cloud space and can be transferred and retrieved any time. In the current chapter, the various aspects of WSI are discussed such as the hardware, software, scanning techniques and various challenges to implement WSI. In addition, the guidelines for diagnostic use of WSI cases have been discussed.